Field of the Disclosure
The disclosure relates to the laser-generated heat treatment of metal and plastic workpieces In particular, the disclosure relates to a laser-based method and laser system for marking thin metal and plastic sheets.
Prior Art
Marking in general is a widely used term including annealing, engraving and ablating techniques well known to one of ordinary skills in the art. Fiber laser annealing creates a permanent mark induced by heat without removing or compromising the material. (color marking actually causes oxide layers to form thus leading to a variety of colors in the marked material.)
The industrial market place has been in need for a way to easily mark metal and plastic with unique identifiers in a way that combines affordability and speed. This need is successfully met by lasers in general and fiber lasers in particular.
There are three primary laser technologies used for marking—fiber lasers, Nd:YAG and Nd:YVO4. While the wavelength from all three technologies is the same and varies around 1064 nm, the system characteristics and the resulting beams can differ in significant ways. One of the largest differences is in the maintenance required for the fiber laser which practically needs no significant maintenance.
It has been noted that marking thin metals, such as stainless steel, and plastics causes the deformation of the workpiece to be treated. For example, stainless steel is marked for a wide variety of purposes: marking of advertising materials, trophies as well as industrial uses. The latter often requires providing insignia associated with a given product or manufacturer on thin metal plates. When a workpiece is treated at high temperatures, it tends to deform. This of course is unacceptable for it destroys the aesthetic appeal of the marked product.
A need therefore exists for a viable laser-based marking process that at least minimizes and preferably completely eliminates deformation of thin metals and plastics.
A further need exists for a laser system operative to carry out the disclosed process.